Make generateReferrerHeader() return a Referrer instead of a String

Source/core/loader/PrerenderHandle.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 28 matching lines @@
 #include "platform/weborigin/ReferrerPolicy.h"
 #include "platform/weborigin/SecurityPolicy.h"
 
 namespace blink {
 
 // static
 PassOwnPtr<PrerenderHandle> PrerenderHandle::create(Document& document, PrerenderClient* client, const KURL& url, const unsigned prerenderRelTypes)
 {
     // Prerenders are unlike requests in most ways (for instance, they pass down fragments, and they don't return data),
     // but they do have referrers.
-    const ReferrerPolicy referrerPolicy = document.referrerPolicy();
-
     if (!document.frame())
         return PassOwnPtr<PrerenderHandle>();
 
-    const String referrer = SecurityPolicy::generateReferrerHeader(referrerPolicy, url, document.outgoingReferrer());
-
-    RefPtr<Prerender> prerender = Prerender::create(client, url, prerenderRelTypes, referrer, referrerPolicy);
+    RefPtr<Prerender> prerender = Prerender::create(client, url, prerenderRelTypes, SecurityPolicy::generateReferrer(document.referrerPolicy(), url, document.outgoingReferrer()));
 
     PrerendererClient* prerendererClient = PrerendererClient::from(document.page());
     if (prerendererClient)
         prerendererClient->willAddPrerender(prerender.get());
     prerender->add();
 
     return adoptPtr(new PrerenderHandle(document, prerender.release()));
 }
 
 PrerenderHandle::PrerenderHandle(Document& document, PassRefPtr<Prerender> prerender)
@@ skipping 32 matching lines @@
 }
 
 
 void PrerenderHandle::detach()
 {
     m_prerender->removeClient();
     m_prerender.clear();
 }
 
 }